Injector nozzle for internal combustion engines



Sept. 11, 1934.

A. A. SIDNEY INJECTOR NOZZLE EOR INTERNAL COMBUSTION ENGINES Filed Aug.8, 1935 /2 6 W $1" 9 mumu LULLLL! IHVENTOR thfir A. Sidney %%W ATTORNEYPatented Sept. 11, 1934 j untrue STA res PATENT FICE INJECTOR. NOZZLEFOR m'rzamr'. COMBUSTION ENGINES Application August d, 1933, Serial No.634,270 In Great Britain August 16, 1932 2 Claims. (81. 299---l07.6)

for the flow of fuel and also to assist atomization of the fuel, whichneedle is retained resiliently. on a seating to close the atomizernozzle by means of spiral spring, or a, diaphragm of thin sheet metal.The needle is raised from its seating against the biassing force of thespring or dia phragm due to the pressure of the fuel, when it isinjected into the combustion chamberunder pressure from a pump or othersimilar device. In atomizers employing sheet metal diaphragms forretaining the needle on its seating, trouble is frequently experiencedthrough the diaphragm fracturing due to fatigue of the metal, and wherea .spiral spring is employed, the leakage of fuel past the atomizerneedle into the spring chamber necessitates the draining of thischamber.

The present invention has for its object to provide an improvedconstruction of atomizer or injector nozzle for internal combustionengines in which the above mentioned disadvantages are eliminated.

According to the invention the injection needle of a fuel injector isblessed on to its seating by means of a closed, transversely corrugatedtubular member which is disposed within the body of the injectorsubstantially in axial alignment with the needle, and with one end inintitwo parts, such for example as may be obtained by a. screwed membersubstantially loosely fitting into the adjacent ends of the parts sothat the stem in rising lifts the needle with it. Alternatively, thestem may be provided at its lower end with a threaded spigot adapted toengage loosely. a correspondingly threaded-hole in the head end of theneedle. These arrangements provide a certain degree of flexibility betwn the two parts, and render unnecessary the ex remely accurate fittingusually essential between the needle and its guide along the wholelength thereof Where no mechanical connection is provided between theparts, the abutting end faces of the needle and the depending stem mustbe accurate- W ly' ground so that when the two faces are pressedtogether by the corrugated member, a joint is oh= tamed therebetweenwhich will, remain substan tially fluid-tight.

Preferably the upper end of the tubular member is also cylindrical, sothat it may be secured in a fluid-tight manner in a circular recessformed in the end of an externally threaded plug, the lat. ter beingadapted to be screwed into-the body portion of the injector in afluid-tight manner. The plug may be provided with a central bore throughwhich passes a rod extending to near the inner face of the disc securedto the other end of the tubular member. This rod may serve as a stop tolimit the contraction of the tubular memher when under fluid pressure,and is conveniently screwed at its outer end into the plug so that itslower end is adjustable relatively to the movable end of the tubularmember. A suitable locking device, such as a lock nut may be provided onthe exterior end of the rod. A cap may enclose the upper' end of theplug and preferably this cap makes a fluid-tight joint between itself,the outer side of the plug and the injector body. A copper or othersuitable washer may be inter-' posed between these parts. j

The plug member may be screwed into or out of the body of the injectorto increase or decrease the biassing pressure of the corrugated tubularmember.

Where the upper end of the tubular member is closed entirely, a stop maybe provided within the body of the injector to co-operate with theexterior of the flanged disc secured to the movable end of the tubularmember, and a rod may be secured within the tubular member to one orother of." the end discs so as to extend to close to the. other disc, tolim't-.-the contraction of the tubular member.

The invention is il ustrated by way of example in the accompanyingdrawing, Fig. 1 of which shows in cross-sectional elevation a preferredembodiment of fuel injector according to the invention, and Fig. 2 ofwhich shows a modified form of injector.

Referring to the drawing, the atomizer comprises a body portion 1 intothe lower end of which is screwed a nozzle portion 2, provided at itslowerend with a nozzle 3 communicating with a seating 4 for an injectorneedle 5 which slidably I iilts a central cylindricalbore in the nozzleportion 2. Theneedle 5 is provided with four longi- -tudinal grooves 18extending from beyond the upper end of the bore in the nozzle portion 2to just above the seating face at the lowerend of the needle, whichgrooves serve for the passage of fuel. Within the body portion 1 isformed an enlarged circular recess 6 with which communicates a fuelinlejgport '7 connected by a pipe 8 to a fuel pump. The upper end of therecess 6 is screw-threaded, and within the recess is housed atransversely corrugatedmetal tubular member 9, the lower end of which ishermetically secured to a flanged disc 10 from which depends astem 11connected through a substantially loose coupling to the upper end of theneedle 5. The upper end of the corrugated tubular member 9 ishermetically secured within a circular recess in the lower end of ascrewed plug 12, adapted to engage the internally threaded upper portionof the recess 6. The plug 12 is formed with an upper extension, througha bore 13 in which a depending rod 14 passes. The upper end of the rod14 is screw-threaded as shown at 20 and engages a correspondinglythreaded portion of the upper part of the bore 13, and an externallyprotruding portion of this threaded part 20 is engaged by a nut 15 tolock the rod 14 in position. The exterior surface ofthe upper part ofthe plug 12 is screw-threaded to accommodate a nut 16 on which ishermetically secured a suitably formed sheet metal cap 17. The lowerpart of the nut 16 is chamfered at its inner circumference and a copperwasher 19 is interposed between this chamfered portion and the exteriorportion of the'joint between the plug 12 and the upper portion of thebody 1.

In operation, the corrugated tubular member 9 retains the needle 5resiliently against its seating 4, the depending rod 14 being adjustedby rotadisc 10, the needle 5 is lifted from its seating and permits thefuel under pressure to be forced through the atomizing nozzle 3 into thecombustion chamber. When the fuel pressure decreases, the needle 5 isreturned to its seating 4 due to the blessing force exerted by thecorrugated tubu-' lar members, and the atomizing nozzle 3 is closed.

In the arrangement shown in Fig. 2, the corrugated tubular member 9 ishermetically closed at its upper end by means of a disc 21- and the rod14 which in this case is not adjustable from the exterior of the device,is secured at its lower end in the flanged disc 10. The upper end of thetubular member 9 is accommodated in a screwed plug member 12, the lowerend of a flange on which, bears on a copper ring 19 to make afluid-tight joint with the upper end face of the injector body 1. Thedepending stem 11 is formed at its lower end with a screwed spigot 22which loosely engages a threaded hole in the upper end of the needle 5.As shown in Fig. 2, a split pin 23 passing laterally through the spigot22 and the needle 5 prevents the spigot from unscrewing from the needle.

In an alternative arrangement, the needle 5 may be formed integrallywith the stem .11 which depends from the flanged disc member 10.

It will be evident that the construction, arrangement and operation ofthe injector device hereinbefore described by way of example, may bemodified without departing from the scope of I the invention.

I claim: I

1. A fuel injector for internal combustion engines comprising a bodyportion, having a fuel inlet and a fuel outlet, a needle valvecontrolling said outlet, 9. closed transversely corrugated flexibletubular member disposed in a recess in said body portion substantiallyin axial alignment with the needle, said tubular member being connectedat one end to the needle valve, and at the other end in a fluid-tightmanner to a screwed plug engaging a threaded upper portion of therecess, a screwed rod engaging a threaded hole in said plug andextending through the centre of the tubular member to near its lowerend, a lock nut for said screwed rod and a, cap member adapted to closethe upper end of said plug and to make a fluid-tight joint between. saidplug and the body portion.

. 1 2. A fuel injector for internal combustion engines comprising a bodyportion, having a fuel inlet and a fuel outlet, a needle valvecontrolling said outlet and a closed, transversely corrugated flexibletubular member disposed in a recess in said body portion substantiallyin axial alignment with the needle said tubular member being flexiblyconnected at one end to the needle valve and at the other to a plugadapted to be secured in a fluid-tight manner in the said recess, and arod disposed axially within said tubular memher so as to restrict thecontraction of said tubular member.

ARTHUR. ALEXANDER SIDNEY.

